Apparatus for peeling and transferring an animal hide to processing

ABSTRACT

A device is described for separating animal skin and for transferring it to further processing through a conveyance channel by using pressure difference. The device comprises a pulling device (3) for separating the skin (2) from the animal carcass (1) and for feeding it to the forward end of a conveyance channel (7), and means (8-10) to generate pressure difference between the ends of the conveyance channel and for separating the conveyed skin (2) form the portage air. According to the invention, the pulling device (3) that engages the other end of the skin (2) further comprises means (4, 5, 12) for feeding the skin (2) to the feed hopper (6) at the forward end of the conveyance channel (7) and for separating it from the pulling device (3) for suction conveyance. In this case, the feeding and separating means (4, 5, 12) are preferably set above the feed hopper (6) so that the skin (2) can be dropped to the feed hopper (6) for the suction conveyance.

The invention is related to a device for separating animal skins, suchas cow or horse skins, and for transferring them through a conveyingpassage, by using pressure difference, to further processing and,particularly, to a device that comprises a pulling device for separatingthe skin from the carcass of the animal and for feeding it to theforward end of the conveying passage, and means for generating pressuredifference between the ends of the conveying passage and for separatingthe conveyed skin from the conveying air.

The term "skin", in this context, refers to the skin of an animal suchas a cow, horse or the like that is stripped in a slaughterhouse. Theterm "stripped" refers to the stripping of the skin from the carcass ofthe animal in question.

Existing slaughterhouses are designed to comprise two storeys and thetreatment of skins generally takes place downstairs beside theskin-pulling device. In such a storey solution the skin is directlydropped downstairs from the roll of the skin pulling device, away fromthe premises of the slaughterhouse. However, the trend today is to buildadvantageous one-storey slaughterhouses, whereby it is not possible toutilise gravity in transferring skins downstairs and, therefore, dirtyskins have to be conveyed from the slaughterhouse to the skindepartment.

The transportation of skins sets limitations on the lay-out planningsince it is generally not possible to locate the skin department besidethe position of skin separation because of other operational startingpoints. The transportation of skins by long and inconvenient conveyorsis not only insanitary and expensive but also requires maintenance.furthermore, the conveyors impede passenger traffic.

The gear for skin transporation known from before includes differentconveyors such as belt or slat conveyors and the blowing by overpressurealong a tabe (pneumatic cannon). It is difficult to automate theequipment for transportation by pneumatic cannon; it requires thebuilding of a hole over 2 metres deep in the floor so that the skin canbe lowered directly from the roll of the pulling device to the transmitarrangement of the funnel-like cannon. The above-mentioned holestructure is insantary and difficult to implement technically,particularly in the existing slaughterhouses. The pneumatic cannonplaced on the floor requires at least one worker to precondition theskin for transportation. In the preconditioning, the skin is folded intoan elongated fold so that it is easy to push to the elongated funneltube of the cannon transmit arrangement and it slides well in transittube without causing blockage.

All these transfer methods and equipment are very expensive andimpractical.

The disadvantages of the above-mentioned devices are now eliminated bytransferring skins in a channel by using pressure difference, ie., bysuction conveyance mainly as defined in the appended claims. In thesolution according to the invention, the transfer of skins is automatedso that it does not require manpower. The transfer by underpressure(vacuum) is a closed transfer system, hygienic and flexible.Consequently, the location of further processing can be selectedaccording to other productional requirements.

The device according to the invention for separating animal skins andtransferring them through a conveyance channel to further processing canbe used to apply suction conveyance because the pulling device thatengages the other end of the skin comprises means for dropping orlowering the skin, with its opposite end in front, to a feed hopper atthe forward end of the conveyance channel, and means for separating theskin from the pulling device for the said suction conveyance. Thefeeding and separating means are preferably located above the feedhopper, whereby smaller and lighter skins can be dropped to the feedhopper whereas larger and heavier skins are gradually lowered, with theopposite end in front, to the feed hopper, in a controlled manner,before the other end is detached from said means.

In a preferred embodiment of the invention, the inner diameter of theconveyance channel is more than about 200 mm, preferably at least about210 mm, for example 210-270 mm whereas the amount of vacuum in thesuction conveyance is at least 40%. The forward end of the conveyancechannel is preferably slightly flattened out, for example, oval.

In a preferred embodiment of the invention, the pulling device is setupwards above an open feed hopper, whereby it comprises a verticallymovable pulling roll. At least one zipper provided with a fastening loopand intended to be attached to the other end of the skin, and at leastone release member for releasing the fastening loop from the skin can bewound on the pulling roll after the skin has been fed gradually and in acontrolled manner to the feed hopper with its opposite end in front. Therelease member is preferably a release chain wound on the pulling rollin the opposite direction with respect to tie zipper. This solution canbe used to quickly and effectively release the skin for the suctionconveyance.

The tail of the conveyance channel can be connected to a separatingchamber which again is connected to an underpressure centre to maintainpressure difference between the ends of the conveyance channel and whichcomprises a lower part with an openable bottom door for the dischargingof the thus conveyed skin from the device for filter processing. Avacuum battery can be used as the underpressure centre.

The need for space of such device is small because there is only oneconveyance channel, such as a test tube, between the pulling device andthe separating chamber, which, when necessary, can criss-cross asdesired in the production premises.In the following the invention isdescribed in detail with reference to the appended drawings in which:

FIG. 1 presents the first part of the device according to the inventionfor the separation of anmal skin from the carcass and for itstransportation to the forward end of the conveyance channel gradually ina controlled way, FIG. 2 is a vertical section of the preferredembodiment of the invention, and FIG. 3 is a cross-cut side view of thefirst part of the device according to FIG. 2.

FIGS. 1 and 2 present the skin of an amal such as a cow, marked byreference number 1, and the skin is marked by 2. Skin 2 is separatedfrom carcass 1 by wounding the skin on pulling roll 4 of pulling device3. First, 2 is attached to fastening loops 5' of zippers 5 of the skinat the skirt of the skin. Next, pulling device 3 winds skin 2 on itspulling roll 4 by simultaneously moving to the lower position above feedhopper 6 of the skin

The transfer tube of the skin is marked reference number 7. Feed hopper6 is attached to the forward end of the transfer tube and skin 2 is fedto the feed hopper together with air. Separation chamber 8 is providedat the opposite end of transfer tube 7 in which skin 2 is separated bycentrifugal force from the portage air and drops down to the bottom ofseparation chamber 8. Portage air is sucked from separation chamber 8through tube 9 to underpressure centre 10. After the transportation,bottom door 11 of separation chamber 8 is opened, whereby skin 2 dropsdown to the collection point for further processing.

As FIG. 3 more closely presents, feed hopper 6 is located so that, whendischarging skin 2 from its pulling roll 4, skin pulling device 3 feedsthe skirt of the skin to transfer tube 7 along with air motion. Skin 2is pulled to transfer tube 7 by suction at the same speed as skinpulling device 3 discharges skin 2 from its pulling roll 4. Thesimultaneous suction both keeps skin 2 straight and shapes it into theform of transfer tube 7, not letting skin 2 pile up and block thejunction between feed hopper 6 and transfer tube 7. Upon skin 2 fullyunrolling from pulling roll 4 through feed hopper 6 to transfer tube 7,release chains 12 of the pulling device are tensioned and release skin 2from chain links 5' of zipper 5. After having been released from links5' of zipper 5 of skin pulling device 3, skin 2 is moved by suctionconveying along tube 7 to separation chamber 8. The suction isdiscontinued and bottom door 11 of separation chamber 8 is opened andskin 2 is dropped to the collection point.

Pulling roll 4 of skin pulling device 3 moves to its upper position forthe next pulling of skin.

EXAMPLE

A transfer device according to FIGS. 1-3 was built, comprising an 8000litre container (underpressure battery) as unde pressure centre 10, fromwhich 40% air had been sucked out, i.e., its vacuum was 400 mbar. Theunderpressure battery was connected to separation chamber 8 by a 100 mmdiameter tube 9 comprising a quickly-openable ball valve. The innerdiameter of transfer tube 7 was 267 mm and the length of tube 7 was 12m, including 2.5 mm of delivery lift. This tube size enabled an easyfeeding of skin 2 to feed hopper 6. when the living weight of cow waslower than 700 kg and when a vacuum of at least about 400 mbar was usedin the suction conveying.

With a living weight of cow increasing to over 1000 kg, skin 2 is solarge and heavy that it must be fed to feed hopper 6 with theabove-mentioned tube size gradually in a controlled way. In the deviceaccording to the invention, the feeding of the skin to the feed hoppercan be cared out easily with success.

An optimal tube size without controlled feed (the skin is sucked to thetansfer tube in a bundle or a ball) for Finnish cow skin is about 210mm, when the amount of underpressure air, 40% of a complete vacuum, isabout 5000 volumetric litre. With the length and diameter of thetransfer tube increasing, the amount of underpressure air increases,correspondingly. When the underpressure is smaller, the diameter of thetube must be correspondingly larger.

The shape of the forward end of transfer tube 7 connected to feed hopper6 also influences the blocking sensitivity (the vault-forming) of thetransfer channel. When a flattened forward end of the tube was used,i.e., the forward end was in the form of an ellipse, the above-mentionedsensitivity to block was decreased considerably.

It is advisable to provide the underpressure centre 10 with a 2000-5000litre underpressure battery to exert a sufficient charging stroke topull the skin to transfer tube 7, simultaneously preventing by-pass flowbetween the skin and the wall of the tube.

What is claimed is:
 1. A device for separating animal skin and fortransferring it to further processing through a conveyance channel byusing pressure difference, comprising a pulling device (3) forseparating the skin (2) from a carcass (1) and for feeding it to theforward end of a conveyance channel (7), and means (8-10) for generatinga pressure difference between the ends of the conveyance channel and forseparating the conveyed skin (2) form the portage air, characterised inthat the pulling device (3) that engages the other end of the skin (2)comprises means (4, 5, 12) for feeding the skin (2) to a feed hopper (6)at the forward end of the conveyance channel (7) and for separating itfrom the pulling device (3) for conveyance by suction.
 2. A deviceaccording to claim 1, characterised in that the feeding and separatingmeans (4, 5, 12) are set above the feed hopper (6) so that the skin (2)can be dropped to the feed hopper (6) for the suction conveyance.
 3. Adevice according to claim 1, characterised in that the feeding andseparating means (4, 5, 12) are set above the feed hopper (6) and thefeeding means (4, 5) are set to gradually ascend to feed the oppositeend of the skin (2) to the feed hopper (6) in a controlled manner beforethe other end of the skin (2) is detached for the suction conveyance. 4.A device according to claim 1, 2 or 3, characterised in that the innerdiameter of the conveyance channel (7) is more than about 200 mm,preferably at least about 210 mm, for example 210-270 mm, with a vacuumof at least about 25-40% in the suction conveyance depending on theweight of the skin (2) and the length of the conveyance channel (7). 5.A device according to claim 1, 2 or 3, characterised in that the forwardend of the conveyance channel (7) is slightly flattened, for example inthe form of an ellipse.
 6. A device according to claim 1, 2 or 3,characterised in that the pulling device (3) comprises, above theupwards-open feed hopper (6), a pulling roll (4) that is essentiallyvertically movable, and at least one zipper (5) provided with a fastingloop (5') and intended to be attached to the other end of the skin (2)and at least one release member (12) to detach the fastening loop (5')from the skin (2) can be wounded on the pulling roll, when it has beenfed gradually in a controlled manner to the feed hopper with itsopposite end in front.
 7. A device according to claim 6, characterisedin that the release member is a release chain (12) wound on the pullingroll (4) in the opposite direction with respect to the zipper (5).
 8. Adevice according to claim 1, 2 or 3, characterised in that the tail ofthe conveyance channel (7) is connected to a separation chamber (8)which again is connected through a tube (9) to an underpressure centre(10) to maintain a pressure difference between the ends of theconveyance channel (7) and which comprises a lower part with a bottomdoor (11) which can be opened to discharge the conveyed skin (2) fromthe device.
 9. A device according to claim 8, characterised in that theunderpressure centre is an underpressure battery (10) from which asufficient amount of air has been removed for the suction conveyance.